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Ever-vigilant is strategy

The discovery of Asian soybean rust in North America in late 2004 (read Background) changed the nature of soybean production in Louisiana as well as throughout the rest of the continent. Farmers must now be ever-vigilant for this disease because once it becomes established, it can spread quickly – potentially destroying entire fields. The fungus is spread by wind-borne spores. First discovered in Asia more than 100 years ago, it has moved to Africa, South America and now here.

The only way to control the disease is early discovery and use of fungicides. Scientists all over the world, including LSU AgCenter scientists, are working to develop varieties of soybeans resistant to this disease – but that solution is at least five years away. Meanwhile, Louisiana and other states have set up a system of sentinel plots to aid in finding the disease.

Identification of Asian Soybean Rust
Symptoms of soybean rust appear identical regardless if they are caused by Phakopsora pachyrhizi or Phakopsora meibomiae. Host plants infected with soybean rust first exhibit small lesions that gradually increase in size and turn from gray to tan or brown. They become polygonally shaped restricted by leaf veins, and may eventually reach 2 to 3 square millimeters.

Asian Soybean Rust Images
Pustules along the viens of the leaf

More images to help with the identification of Asian soybean rust

Brazilian Soybean Rust Expert Says Check Fields Often; Hurricane Could Blow In More Disease Spores
soybean rust

The trouble with Asian soybean rust, the disease most feared by soybean farmers, is that the spores that cause it can blow into a field from anywhere, anytime. And Hurricane Dennis could bring in a new wave from South America.